The private gene-hunting company Celera Genomics has announced that it has 97% of all human genes in its grasp.

The company is currently racing against the publicly-funded Human Genome Project (HGP) to complete a readout of the human genetic blueprint.

Celera says it already has the DNA sequences for 90% of the human genome, and believes this data covers all but 3% of all human genes.

It will become an era of personalised medicine

Dr Craig Venter

It intends to reveal the precise gene sequences and locations in the genome using advanced statistical analysis and DNA databases already in the public domain.

It expects to complete the sequencing work later this year having only begun the investigation last September. The HGP, by contrast, was formally started in 1990.

It has speeded up its work and now expects to have a rough draft of the genome ready for publication in just a few months.

Tailored drugs

Scientists say understanding the human genome will usher in a new era of medicine that will allow pharmaceutical companies to make tailored drugs for people.

"We think that is potentially an understatement," said Dr Craig Venter, president and chief scientific officer of Celera.

"It will become an era of personalised medicine that will empower all of us as individuals to have more control over our personal lives."

Celera will attempt to patent those parts of the genome it thinks are important and useful, charging researchers who want access to the sequences. Celera has already filed preliminary patents for 6,500 genes.

But Craig Venter said most of Celera's work on the genome will be available without restriction.

"We will make the basic sequences available through our website and DVD disk in such a way that it cannot be redistributed but everyone can use it freely," he said.

Sequencing machines

Celera uses 300 DNA-sequencing machines, running 24-hours a day. The data they produce are analysed by the most powerful super-computer in private hands anywhere in the world.

The DNA data are obtained by analysing randomly produced fragments of all 24 human chromosomes. So far, Celera says this has produced 2.58 billion base pairs of unique sequence that have been calculated to cover 81% of an estimated genome size of 3.18 billion base pairs.

But when this is combined with information from the public databases, Celera has coverage of over 90% of the human genome.

And because the genome contains large, repeated sequences of apparently "junk" DNA, Celera believes the information now in its computers probably accounts for just over 97% of all genes.

Craig Venter announced the progress saying that because their method of DNA analysis focuses on the entire genome at once, human genes could be identified at the same time.

'Shotgun' technique

"The early phase of sequencing the human genome is especially important for gene discovery," he added. "We are rapidly coming to an end of that phase. Our statistical analysis and comparison to known genes suggest that greater than 97% of all human genes are represented in our database.''

The speed at which Celera has been able to read human DNA has been remarkable and has shocked many researchers.

The whole genome "shotgun" technique used by Celera was pioneered by its scientists to sequence the first complete genome (of a virus) at The Institute for Genomic Research in 1995.

The shotgun technique involves randomly shearing the human chromosomes into millions of fragments of between 2,000 and 10,000 base pairs in length. The fragments are then inserted into the E. coli bacterium which produces millions of copies of each one for analysis.

Celera scientists then read the sequence of each fragment. The millions of sequences of genetic code are then matched up by using computers to spot identical overlaps.

However, whoever completes the genome first will in one sense only have reached the start. The map contains so much rich information about the workings of the human body that it will takes many years to understand it and utilise it.

"Over half the genes being discovered are new to science," Dr Venter said. "It will take decades and decades and decades of research to understand this vast quantity of information."